Single-phase motor.



W. J. BRANSON.

SINGLE PHASE MOTOR.

APPLICATION FILED'SEPT. a, 1908.

1,01 3,1 1 9. V I Patented Jan. 2, 1912.

WITNESSES I ENTO R v ATTQRNEY vj UNITED S ATES PATENT oFFIoE.

WALTER J. imANsoN, or WTLKINSBURG, PENNSYLVANIA, AssIeNoR, .BY MESNE ASSIGNMENTS, TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, OF EAST PITTSBURGH, PENNSYLYANIA, A CORPORATION OF'PENNSYLVANIA.

SINGLE-PHASE moron. I

Specification of Letters Patent.

Patented Jan. 2,1912.

7 Application filed Septmber B, 1908. Serial No. 452,090. l

. To all whom it may, concern:

Be it knownthat I, WALTER J. BRANSON, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of, Pennsylvania, have invented a new and useful" Improvement in Single- "Phase Motors, of which thefollowin'g is a said speeds.

specification.

My invention relates to single-phase alternating current induction motors an ticularly to starting means therefor The object of my invention is to so constructand arrange the windings of singlephase induction motors as to adapt such motors for operation at a pluralityof substantially constant speeds and to permit starting thereof when arranged for any of The windings of poly-phase induction motors are frequently so arranged that the numbers of poles and, consequently, the motor speeds may be changed at will by the windings,

terior thereto. In order that single-phase induction motors may be similarly con- 'structed and operated, it is highly desirable and sometimes quite essential, especlallywhen the adjustment of the connections of the windings is made within the motors,

that the auxiliary windings be arranged to 7 effect starting of the motors irrespective of the number of poles produced by the main windings. V

The object of the present'invention is to secure this result without changing the connections of the auxiliary windings when the connections of the main windings are changed.

My invention is illustrated diagrammatically in the accompanying "drawings, Figure 1 of which shows the connections of the windings as made within a'motor for slow speeds. Fig. 2 shows-thewindings of the motor shown in Fig. 1 when arranged.

for a higher speed, and Fig. '3 illustrates an. external controller for changing the cirouit connections of the motor.

For the sake of simplicity, the invention is here shown as applied to motors in which the main windings may be arranged to produce either two or fourpoles, though, of course, it will be readily understood that it is not restricted, in its application, to such motors, but may be employed equally well in connection with motors in which the "windings are adapted to produce other numbers of poles bearing either the same rat-i0 as that above specified or a different ratio.

Each ofthe motors illustrated comprises a main winding of low ohmic resistance that is divided into two sections 1 and 2, an auxiliary winding of high ohmic resistance con '65 sistingof three sections 3, 4,-and 5, and a r0- tatable secondary member 6 that carries parts of a suitable centrifugally actuated switch'7, such as that shown, whereby the circuit of the auxiliary winding. is interrupted, in the usual manner, when the motor attains a predetermined speed. The sections 3 and 40f the auxiliary primary winding are adapted to produce fluxes of the same sign simultaneously, and, since the section 4: is of approximately twice the length or polar pitch of the sections 3 and 5, approximately three-fourths of the auxiliary winding produces a flux of one sign. The sec tion 4 of the auxiliary winding produces a pole the center of which is disposed approxi mately midway between the adjacent extremities of the sections 1 and 2 of the main primary winding, the centers of the poles produced by the sections 3 and 5 being disposed'approxhnately 135 electrical degrees? therefrom.

In Fig. 1, sections 1 and 2 of the main primary windingare arranged to produce poles of the same signsimultaneously, the poles of the opposite sign being consequent and disposed midway between the poles which correspond, in position, to the windings. The motor then has four poles and operates at its lower speed. In Fig. 2, however, the sections 1- and 2 produce poles of opposite sign, there then being only two poles, with the result that the motor will operate at its higher speed The con-nee;

tionsjand. arrangements 'of' the auxiliary gard to the directions ofthe torques or rotat-mg fields produced frespectively by .ad-

jacent cooperating portions of the windings. vIn Fig.1 a torque'or rotating field Wlll be produced in the-directionof the arrow 8 by sect1on 3; of the ,r aux-iiiary winding acting.

inconjiinction with-section 1 of the main winding, $11108 theauxiliary winding is of high ohmic'resistance and low inductance and the current therein leads thatin the 'main winding, w hich is of lower ohmic resistance and high inductance, and the rota'ti'ng field moves. away from the pole produced by the current that is in the lead and toward the pole produced by the current that lags. For the same reason, section 4 of the auxiliary winding, cooperating wlth section lot the main winding, causes a roi combination wlth a main-v prlmary-windlng tating field .in the direction of the arrow 9, and, cooperating with section 2 of the mainwinding, causes a rotatingfieldin the direction of the .arrow 10. Similarly,.section 5 of the auxiliary winding, cooperating with section 2 of the main winding,' -causes a 1'0- tating field inthe "direction of vthe arrow 11. It will be observed that the arrows 9 and 10 are oppositely directed, the -result beingtha't the rotating fields represented thereby 0on1 sequently neutralize each other and rota tion ofthe member 6 is. eife'cted-only'bythe fields represented by the arrowsf8- and 11 In Fig. 2 the .rotating {fields producedby the sections 3and4 of the" auxili'any-wlnding, cooperatingwith section fl of the main; 1 I winding,are similarly directedyas irf Fig. l,

and'are also designated by thie arrdws 8 and .9. Sectionstand 5'of-the auxiliaryjwind" ing', however, cooperating with'section2 of the .main winding now produce rotating fields represented by arrows-12and-13; It

I will be observedthat the arrows8 arrows 9 and 12) are similarly; directed. and accordingly produce rotation of the member 6.] Thus it isseen that, whether the-main a primary Winding is arranged to produce two are now oppositely directed,',-whereas the},

fconn'ections for difierent numbers of poles of r the main winding;

orfourpoles, the auxiliary winding serves to effect starting ofthe "motor. lt.is', of

course, true that onlyone-half of the torques.

exerted within, the motor are available for useful purposes in each case, but that is sufficient tocause'th'e motor to attain such speed-that the auxiliary winding mayp-be thrown out --o service by thefcentrifugal the. same, irrespective of. the number of poles produced by the main switch andlth'e main'winding be relied upon to efiectfu'rthe'r increase of speed .until full :speed is atta1ne.d.

1 When the motor is'to' be usedcontinuously, orduring'long'periods of time for operation at one speed, it maybe desirable to connect the windings permanently "forthat speed,

' as illustrated in Figs. 1' and 2, but if the motor is to be used intermittingly for opermay be adapted, an external'switch 15 may ation at the different speeds for Whichit;

be employed for changing the connections to the motor, the switch here shown being only illustrative'ofv any suitable and convenient means that may be employed forthe purpose. In order to connect the main windings of the motors for four poles and.

the lower speed, the switch-15 should be moved to the 'rlght, the-connections thus efl'ected being illustrated in Fig. 1, and, if

it is desired to operate the motor "at the higher speed, the switch 15 should be moved to the left, in which case the connections. 'e'fiected will be those illustrated in Fig. 2.

I claim as my invention: 1 1. In a single-phase. induction motor, the

'adaptedgfor circuit connections to produce an auxiliary winding adapted tocooperate a plurality'of numbers of magnetic poles, of 1 with the main winding in starting the motor v and without change in-itscircuit connectionsfor difiierent'numbers of poles ofthe main winding; a

' F 2. In a single-phase llldlltltlOl'lll'lOtOI, the combination with a main primary winding adapted for circuit connections to produce two numbers of magnetic poles, one of which isdou ble the'other, of an auxiliary winding "adapted to cooperate with the main wind- "1 ing' in' starting the motor and without changein its circuit connections for different 105 In a single-phase induction motor, the

numbers of poles of the'main winding.

combinationwith a. main primary winding adapted for ClIClllt'GOnIlGCtlOnS to produce in starting and-without change in its circuit 4.1m a'slngle-phas e induction motor, the

v'vith'the main winding in'starting the motor and three-fourths of which is adapted to produce a flux of one polarity.

- 5.'ln a single-phase induction motor, the

combination with a' main distributed pri- 1 a pluralityo'f numbers of magnetic poles, of an'auxil1ary winding, one-half of which is effective tocooperatewith the main winding mary winding comprising two polar sections the auxiliary winding being disposed apand adapted for circuit connections to proroximat'ely 135 electrical degrees thereduce either two or four poles, of an auxiliary From. 1 distributed windin comprising three sec- In testimony whereof, I have hereunto '5 tions f one of whic is of approximately subscribed my name this 3rd day. of Sep-' 5 double the polar pitch of theothertwo and tember, 1908. the center of the pole produced by which is WALTER J. BRANSON. disposed between extremities of the sections Witnesses: v p of the main windin andthe centers of the- F. R. KUNKEL, 10 poles produced by t e-other two sections of BIRNEY HINES. 

